Have you ever wondered if adding a separate log device can improve your performance? zilstat is a DTrace script which helps answer that question. I have updated zilstat to offer the option of tracking ZIL activity on a per-txg commit basis. By default, ZIL activity is tracked chronologically at fixed intervals. Adding the per-txg commit measurement improves the estimation of the size of a separate log device. zilstat can be found at http://www.richardelling.com/Home/scripts-and-programs-1/zilstat Enjoy -- richard